66 KKPORT ON THE PENNATULIDA. 



an inner circular layer, and an inner lining of endoderm cells continuous, 

 as is seen in the fourth polype of Fig. 5, with the endoderm lining the 

 body-cavity of the polype. 



Our specimens of Virgrdaria are in rather worse histological con- 

 dition than those of either Funiculina or PennatuJa, and we have been 

 unable to determine with cortainty whether thread-cells, the special 

 defensive and offensive weapons of Calenterata, are present or absent. 

 The point is one of some importance ; for should they prove to be 

 absent we might find in this the explanation of Virgularia being 

 habitually devoured as food, while Funiculina and Pennatula are 

 allowed to go unharmed. 



This explanation is of course a pui-ely hypothetical one, resting 

 merely on our inability to find thread-cells in imperfectly preserved 

 specimens. We have thought it worth while to record it, however, as 

 it is one which the Society may have an opportunity at some future 

 time of testing directly, and also because there are certain other 

 facts which seem to make it not altogether improbable. Thus we 

 know from the observations of Kolliker, Koren and Danielssen, and 

 others, that the truncation of the upper end occurs normally in certain 

 species of Virgularia, but not in others ; i.e., according to our theory, 

 that certain species of T";r/7(/Za)v'rt are habitually eaten as food by fish or 

 other marine animals, while other species escape. We know also from 

 an observation of Rumph made more than a century ago, that some 

 species of Virgularia possess a very remarkable power of stinging, due 

 evidently to the possession of thread-cells, while in other species this 

 stinging power is not perceptible, at any rate to ourselves. 



Rumph's observations are so important that we shall quote them 

 here. His specimens of Virgularia, of a species which has been since 

 named by Kolliker, in honour of its discoverer, Virgularia Ixumpliii, 

 were obtained at Amboyna, a small island in the Malay Archipelago, 

 east of Celebes. Concerning them, he says :* — " If one handles them 

 incautiously one experiences a burning sensation, and the hand 

 becomes red ; then ensues a violent itching, followed by the appearance 

 of blisters, as if one had been stung by nettles, lasting for three days." 

 Concerning another species, Virgularia juncea, Rumph remarks that he 

 has not noticed that it causes any distinct burning or itching in the hand, 

 although he had pulled them up by hundreds. Neither does Darwin, in 

 his account of the South American Virgularia, say anything concerning 

 it possessing a power of stinging, which he could hardly have failed to 

 notice had it been actually present. We know also that both of these 

 latter species are habitually truncated, so that there seems sufficient 

 evidence to warrant our making the suggestion that Virgularia viirabilis 

 may be devoured because it possesses no thread-cells, while Funiculina 

 escapes because it is i-ichly armed with these defensive weapons. 



Bumph: "T' Amboin 'sche Eariteitkamer," p. 48, Amsterdam, 1741. 



